CN111699237A

CN111699237A - Refrigerator oil and working fluid composition for refrigerator

Info

Publication number: CN111699237A
Application number: CN201980010938.2A
Authority: CN
Inventors: 庄野洋平; 奈良文之; 大城户武; 尾形英俊
Original assignee: Eneos Corp
Current assignee: Eneos Corp
Priority date: 2018-02-07
Filing date: 2019-02-06
Publication date: 2020-09-22
Anticipated expiration: 2039-02-06
Also published as: US11384309B2; KR102516452B1; JPWO2019156124A1; US20210032558A1; CN111699237B; JP7175288B2; KR20200118086A; WO2019156124A1

Abstract

One mode of the invention isA refrigerator oil, comprising: a base oil comprising an ester of an alcohol and a fatty acid, and a compound represented by the following formula (1), wherein the kinematic viscosity of the refrigerator oil at 40 ℃ is 10mm²The ratio of the water to the water is less than s. In the formula (1), R¹And R²Each independently represents a 1-valent hydrocarbon group, R³Represents a 2-valent hydrocarbon group, R⁴Represents a hydrogen atom or a 1-valent hydrocarbon group.

Description

Refrigerator oil and working fluid composition for refrigerator

Technical Field

The present invention relates to a refrigerator oil and a working fluid composition for a refrigerator.

Background

A refrigerator, an air conditioner, or the like includes: a compressor for circulating a refrigerant in the refrigerant cycle system. The compressor is filled with a refrigerating machine oil for lubricating the sliding member. In general, as the viscosity of the refrigerating machine oil is lower, the stirring resistance and the friction of the sliding portion can be reduced, and therefore, the reduction in the viscosity of the refrigerating machine oil leads to energy saving of the refrigerating machine. Patent document 1 discloses a predetermined refrigerator oil having VG3 or more and VG8 or less, for example.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2006/062245

Disclosure of Invention

Problems to be solved by the invention

However, when the viscosity of the refrigerating machine oil is low, it becomes difficult to maintain the oil film of the sliding portion, and therefore, for example, there is a fear that the wear resistance cannot be maintained. Therefore, an additive for improving the wear resistance is added to the refrigerator oil. On the other hand, since such additives may lower the stability of the refrigerating machine oil, it is desirable that the amount of the additives is as small as possible. That is, when the same amount of additive is added, a refrigerator oil having a higher effect of improving wear resistance is required.

The object of the invention is therefore: the effect of improving the wear resistance is large in a low-viscosity refrigerator oil.

Means for solving the problems

One embodiment of the present invention is a refrigerator oil including: a base oil comprising an ester of an alcohol and a fatty acid, and a compound represented by the following formula (1), wherein the kinematic viscosity of the refrigerator oil at 40 ℃ is 10mm²The ratio of the water to the water is less than s.

In the formula (1), R¹And R²Each independently represents a 1-valent hydrocarbon group, R³Represents a 2-valent hydrocarbon group, R⁴Represents a hydrogen atom or a 1-valent hydrocarbon group.

Another aspect of the present invention is a working fluid composition for a refrigerator, including a refrigerator oil and a refrigerant, the refrigerator oil including: a base oil comprising an ester of an alcohol and a fatty acid, and a compound represented by the above formula (1), wherein the refrigerating machine oil has a kinematic viscosity of 10mm at 40 ℃²The ratio of the water to the water is less than s.

The alcohol preferably contains at least 1 selected from the group consisting of 1-and 2-membered alcohols. The fatty acid preferably comprises a branched fatty acid. In this case, a greater effect of improving the abrasion resistance is obtained.

The base oil may have a non-polarity index of 60 or less.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention can provide a large effect of improving the wear resistance of a low-viscosity refrigerator oil.

Drawings

Fig. 1 is a schematic diagram showing an example of a refrigerator configuration.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

The refrigerator oil of one embodiment comprises a base oil comprising an ester of an alcohol and a fatty acid. The alcohol may be an aliphatic alcohol. The aliphatic alcohol is optionally straight-chain or branched. The carbon number of the alcohol may be, for example, 3 or more, 4 or more, or 5 or more, and may be 12 or less, 10 or less, or 8 or less.

From the viewpoint of obtaining a greater effect of improving the abrasion resistance, the alcohol preferably contains at least 1 selected from the group consisting of 1-and 2-membered alcohols, and more preferably contains at least 1 selected from the group consisting of 1-and 2-membered aliphatic alcohols.

The ratio of 1-and 2-membered alcohols in the alcohol (total) may be 50% by mass or more, 70% by mass or more, or 90% by mass or more. The ratio of the 1-membered aliphatic alcohol and the 2-membered aliphatic alcohol in the alcohol (total) may be 50% by mass or more, 70% by mass or more, or 90% by mass or more. The alcohol may be formed of only at least 1 selected from the group consisting of 1-and 2-membered alcohols, or may be formed of only at least 1 selected from the group consisting of 1-and 2-membered aliphatic alcohols.

The 1-membered aliphatic alcohol may be, for example, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, or the like. These 1-membered aliphatic alcohols are optionally linear or branched.

Examples of the 2-membered aliphatic alcohol include 1, 3-propanediol, 1, 2-propanediol, 1, 4-butanediol, 1, 2-butanediol, 2-methyl-1, 3-propanediol, 1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 2-ethyl-2-methyl-1, 3-propanediol, 1, 7-heptanediol, 2-methyl-2-propyl-1, 3-propanediol, 2-diethyl-1, 3-propanediol, 1, 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, 1, 11-undecanediol, and 1, 12-dodecanediol.

The carbon number of the fatty acid may be, for example, 4 or more, 5 or more, or 6 or more, and may be 20 or less, 15 or less, or 10 or less. The fatty acid may optionally contain a straight-chain fatty acid or a branched-chain fatty acid, and preferably contains a branched-chain fatty acid from the viewpoint of obtaining a greater effect of improving the abrasion resistance.

The fatty acid preferably contains at least 1 selected from the group consisting of C4-12 straight-chain fatty acids and C4-12 branched fatty acids, and more preferably contains at least 1 selected from the group consisting of C6-8 branched fatty acids, from the viewpoint of achieving a higher improvement effect in abrasion resistance while reducing viscosity. Such a fatty acid may be, for example, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-methylhexanoic acid, or 2-ethylhexanoic acid.

The ratio (total) of the C4-10 linear fatty acid and C4-10 branched fatty acid to the fatty acid may be 50 mass% or more, 70 mass% or more, or 90 mass% or more. The proportion (total) of the branched fatty acids having 6 to 8 carbon atoms in the fatty acids may be 50 mass% or more, 70 mass% or more, or 90 mass% or more. The fatty acid may be formed of only at least 1 selected from the group consisting of C4-10 straight-chain fatty acids and C4-10 branched-chain fatty acids, or may be formed of only at least 1 selected from the group consisting of C6-8 branched-chain fatty acids.

The ester may contain only an ester of a 1-membered alcohol (preferably a 1-membered aliphatic alcohol) and a fatty acid, or may contain only an ester of a 2-membered alcohol (preferably a 2-membered aliphatic alcohol) and a fatty acid, and from the viewpoint of obtaining a greater effect of improving the abrasion resistance, may contain only an ester of a 1-membered alcohol (preferably a 1-membered aliphatic alcohol) and a fatty acid, and an ester of a 2-membered alcohol (preferably a 2-membered aliphatic alcohol) and a fatty acid.

The kinematic viscosity of the base oil at 40 ℃ may be, for example, 1mm²1.5mm over/s²More than s, or 2mm²More than s, preferably 10mm from the viewpoint of obtaining a greater effect of improving wear resistance and also excellent wear resistance (the amount of wear can be reduced)²Less than s and 9mm²Less than s, or 8mm²The ratio of the water to the water is less than s. The kinematic viscosity of the base oil at 100 ℃ may be, for example, 0.5mm²1mm above/s²More than s, or 1.5mm²More than s, preferably 8mm from the viewpoint of obtaining a greater effect of improving wear resistance and also excellent wear resistance (the amount of wear can be reduced)²Less than s and 5mm²Less than s, or 2.5mm²The ratio of the water to the water is less than s. The kinematic viscosity in the present specification means a kinematic viscosity according to JIS K2283: 2000 measuredKinematic viscosity.

The nonpolar index of the base oil may preferably be 60 or less, 55 or less, 50 or less, 45 or less, or 40 or less, or may be 20 or more, 30 or more, or 35 or more. When a fatty acid ester having a nonpolar index of 60 or less is used, the wear resistance or wear resistance improving effect (improvement rate) by the compound represented by formula (1) is further improved as compared with the case of using a fatty acid ester having a nonpolar index exceeding 60. In addition, the effect (improvement rate) of improving the wear resistance or abrasion resistance based on the compound represented by the formula (1) tends to be higher in the case of a branched fatty acid ester as the base oil than in the case of a linear fatty acid ester as the base oil. The nonpolar index of the fatty acid ester is calculated by the following formula (a).

Nonpolar index (number of carbon atoms × molecular weight)/(number of ester groups × 100) … (a)

In the formula (a), the number of carbon atoms represents the number of carbon atoms constituting the fatty acid ester, the molecular weight represents the molecular weight of the fatty acid ester, and the number of ester groups represents the number of ester groups contained in 1 molecule of the fatty acid ester.

The base oil may contain other known base oils in addition to the above esters. The content of the ester may be 50% by mass or more, 70% by mass or more, or 90% by mass or more based on the total amount of the base oil. The base oil may be formed from only the above-mentioned esters.

The content of the base oil may be 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, or 95 mass% or more, and may be 99.5 mass% or less, 99 mass% or less, or 98.5 mass% or less, based on the total amount of the refrigerator oil.

The refrigerator oil further contains a compound represented by the following formula (1).

In the formula (1), R¹And R²Each independently represents a 1-valent hydrocarbon group. Examples of the 1-valent hydrocarbon group include an alkyl group and an aryl group. R¹And R²The number of carbon atoms of the 1-valent hydrocarbon group may be 1 or more, 2 or more, or 3 or more, or 10 or less, 9 or less, or 8 or less, respectively. R¹And R²The total number of carbon atoms in the 1-valent hydrocarbon group may be 2 or more, 3 or more, or 4 or more, or 20 or less, 19 or less, or 18 or less.

In the formula (1), R³Represents a 2-valent hydrocarbon group. Examples of the 2-valent hydrocarbon group include an alkylene group and the like. R³The number of carbon atoms of the 2-valent hydrocarbon group may be 1 or more, 2 or more, or 3 or more, or 10 or less, 9 or less, or 8 or less.

In the formula (1), R⁴Represents a hydrogen atom or a 1-valent hydrocarbon group. Examples of the 1-valent hydrocarbon group include an alkyl group and the like. R⁴The number of carbon atoms in the 1-valent hydrocarbon group may be 1 or more, 2 or more, or 3 or more, or 10 or less, 9 or less, or 8 or less.

The compound represented by the formula (1) is preferably a compound represented by the following formula (2).

In the formula (2), R¹、R²And R⁴And R in the formula (1)¹、R²And R⁴Are synonymous respectively. R⁵And R⁶Each independently represents a hydrogen atom or an alkyl group. The alkyl group is optionally either linear or branched, and is preferably linear. The number of carbon atoms of the alkyl group may be, for example, 1 to 4, 1 to 3, or 1 to 2. Preferably R⁵And R⁶Is a hydrogen atom. More preferably R⁵And R⁶One is an alkyl group and the other is a hydrogen atom.

Specific examples of such compounds include 3- (diisobutyl-thiophosphoryl mercapto) -2-methyl-propionic acid, ethyl 3- [ [ bis (1-methylethoxy) phosphinothio ] thio ] propionate, 3- (O, O-diisopropyl-dithiophosphoryl) -propionic acid, 3- (O, O-diisopropyl-dithiophosphoryl) -2-methyl-propionic acid, 3- (O, O-diisobutyl-dithiophosphoryl) -2-methyl-propionic acid, and alkyl esters of these compounds such as ethyl esters.

From the viewpoint of further improving the wear resistance, the content of the compound represented by formula (1) is preferably 0.001 mass% or more, more preferably 0.005 mass% or more, and even more preferably 0.01 mass% or more, based on the total amount of the refrigerator oil. From the viewpoint of improving stability, the content of the compound represented by formula (1) is preferably 5% by mass or less, more preferably 4% by mass or less, and still more preferably 3% by mass or less, based on the total amount of the refrigerator oil. The content of the compound represented by formula (1) is preferably 0.001 to 5 mass%, 0.001 to 4 mass%, 0.001 to 3 mass%, 0.005 to 5 mass%, 0.005 to 4 mass%, 0.005 to 3 mass%, 0.01 to 5 mass%, 0.01 to 4 mass%, or 0.01 to 3 mass% from the viewpoint of further improving the abrasion resistance and stability.

When the refrigerator oil is obtained with excellent stability by suppressing initial oxidation to a low level and further contains a phosphorus-based extreme pressure agent (described later in detail) other than the compound represented by formula (1), the content of the compound represented by formula (1) may be 1% by mass or less, 0.1% by mass or less, 0.06% by mass or less, or 0.04% by mass or less, or may be 0.001 to 1% by mass, 0.001 to 0.1% by mass, 0.001 to 0.06% by mass, 0.001 to 0.04% by mass, 0.005 to 1% by mass, 0.005 to 0.1% by mass, 0.005 to 0.06% by mass, 0.01 to 1% by mass, 0.01 to 0.1% by mass, 0.06% by mass, or 0.01 to 0.04% by mass, based on the total amount of the refrigerator oil, from the viewpoint of further improving the effect of the combination.

The refrigerator oil may further contain a phosphorus-based extreme pressure agent other than the compound represented by formula (1). The phosphorus-containing extreme pressure agent may contain phosphorus in the molecule. The phosphorus-based extreme pressure agent may be, for example, a phosphoric acid ester, an acidic phosphoric acid ester, an amine salt of an acidic phosphoric acid ester, a chlorinated phosphoric acid ester, a phosphorous acid ester, a thiophosphoric acid ester, or the like.

Examples of the phosphate ester include tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, triundecyl phosphate, tridodecyl phosphate, tritridecyl phosphate, tritetradecyl phosphate, tripentadecyl phosphate, trihexadecyl phosphate, triheptadecyl phosphate, trioctadecyl phosphate, triolenyl phosphate, triphenyl phosphate, tricresyl phosphate, tris (ethylphenyl) phosphate, tris (propylphenyl) phosphate, tributylphenyl) phosphate, trixylyl phosphate, cresyldiphenyl phosphate, and xylyldiphenyl phosphate. The phosphate is preferably triphenyl phosphate or tricresyl phosphate.

As the acid phosphate ester, there may be mentioned monobutyl acid phosphate ester, monopentyl acid phosphate ester, monohexyl acid phosphate ester, monoheptyl acid phosphate ester, monooctyl acid phosphate ester, monononyl acid phosphate ester, monodecyl acid phosphate ester, monoundecyl acid phosphate ester, monododecyl acid phosphate ester, monotridecyl acid phosphate ester, monotetradecyl acid phosphate ester, monopentadecyl acid phosphate ester, monohexadecyl acid phosphate ester, monopecyl acid phosphate ester, monostearyl acid phosphate ester, monooleenyl acid phosphate ester, dibutyl acid phosphate ester, dipentyl acid phosphate ester, dihexyl acid phosphate ester, diheptyl acid phosphate ester, dioctyl acid phosphate ester, dinonyl acid phosphate ester, didecyl acid phosphate ester, diundecyl acid phosphate ester, didodecyl acid phosphate ester, didecyl acid phosphate, Ditridecyl acid phosphate, ditetradecyl acid phosphate, dipentadecyl acid phosphate, dihexadecyl acid phosphate, diheptadecyl acid phosphate, dioctadecyl acid phosphate, dioleyl acid phosphate, and the like.

Examples of the amine salt of the acidic phosphoric acid ester include salts of amines such as methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, and trioctylamine of the acidic phosphoric acid ester described above.

Examples of the chlorinated phosphate include tris (dichloropropyl) phosphate, tris (chloroethyl) phosphate, tris (chlorophenyl) phosphate, and polyoxyalkylene bis [ di (chloroalkyl) ] phosphate. Examples of the phosphite include dibutyl phosphite, dipentyl phosphite, dihexyl phosphite, diheptyl phosphite, dioctyl phosphite, dinonyl phosphite, didecyl phosphite, diundecyl phosphite, didodecyl phosphite, dioleyl phosphite, diphenyl phosphite, ditolyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl phosphite, trioctyl phosphite, trinonyl phosphite, tridecyl phosphite, triundecyl phosphite, tridodecyl phosphite, triolenyl phosphite, triphenyl phosphite, and tritolyl phosphite.

Examples of the thiophosphate include tributyl thiophosphate, tripentyl thiophosphate, trihexyl thiophosphate, triheptyl thiophosphate, trioctyl thiophosphate, trinonyl thiophosphate, tridecyl thiophosphate, triundecyl thiophosphate, tridodecyl thiophosphate, tritridecyl thiophosphate, tritetradecyl thiophosphate, tripentadecyl thiophosphate, trihexadecyl thiophosphate, triheptadecyl thiophosphate, trioctadecyl thiophosphate, triolenyl thiophosphate, triphenyl thiophosphate, tricresyl thiophosphate, trixylyl thiophosphate, cresyl diphenyl thiophosphate, and xylyl diphenyl thiophosphate. The thiophosphate is preferably triphenyl thiophosphate.

From the viewpoint of further excellent wear resistance, the content of the phosphorus-based extreme pressure agent may be 0.1 mass% or more, 1 mass% or more, 1.5 mass% or more, or 1.6 mass% or more, or may be 5 mass% or less, 3 mass% or less, 2.5 mass% or less, or 2 mass% or less, based on the total amount of the refrigerator oil.

When the refrigerator oil further contains a phosphorus-based extreme pressure agent, the ratio of the content of the compound represented by formula (1) to the content of the phosphorus-based extreme pressure agent (mass ratio, compound represented by formula (1)/phosphorus-based extreme pressure agent) may be 0.0001/1 or more, 0.0002/1 or more, or 0.0005/1 or more, or may be 1/1 or less, 0.5/1 or less, 0.1/1 or less, 0.05/1 or less, or 0.01/1 or less.

The kinematic viscosity at 40 ℃ of the refrigerating machine oil may be, for example, 1mm²1.5mm over/s²More than s, or 2mm²More than s, preferably 10mm from the viewpoint of obtaining a greater effect of improving wear resistance and also excellent wear resistance (the amount of wear can be reduced)²Less than s and 9mm²Less than s, or 8mm²The ratio of the water to the water is less than s. The kinematic viscosity of the refrigerator oil at 100 ℃ may be, for example, 0.5mm²1mm above/s²More than s, or 1.5mm²More than s, preferably 8mm from the viewpoint of obtaining a greater effect of improving wear resistance and also excellent wear resistance (the amount of wear can be reduced)²Less than s and 5mm²Less than s, or 2.5mm²The ratio of the water to the water is less than s.

For the ISO viscosity classification of refrigerator oils, provided that the kinematic viscosity of the refrigerator oil at 40 ℃ is 10mm²The content of the monomer is not particularly limited. The ISO viscosity classification of the refrigerator oil is classified, for example, as VG2, 3,5, 7, and 10, and from the viewpoint of ensuring low friction in the fluid lubrication region, VG10 or less is preferable, VG7 or less is more preferable, and VG5 or less is further preferable. For example, the refrigerating machine oil of VG7 or 5 generally has a low friction coefficient in the fluid lubrication region compared with a refrigerating machine oil having a higher viscosity grade than the lubricating machine oil, but the lubricating property in the mixed lubrication and/or boundary lubrication region tends to be deteriorated and the friction coefficient tends to be high. However, by adding the compound represented by the above general formula (1) in the present invention, the lubricity in the mixed lubrication and/or boundary lubrication region is significantly improved, and also becomes conducive to low friction. The improvement degree is higher when the refrigerating machine oil is VG10 or less. The ISO viscosity classification herein refers to the viscosity grade specified in JIS K2001 (1993) "Industrial lubricating oil-ISO viscosity classification" or ISO3448/1992 "Industrial liquid lubricants-ISO viscostatic viscosity classification".

The refrigerating machine oil may have a flash point of 100 ℃ or higher, 110 ℃ or higher, or 120 ℃ or higher from the viewpoint of safety, and may have a flash point of 155 ℃ or lower, or 145 ℃ or lower from the viewpoint of reducing the viscosity. The flash point in the present specification means a flash point according to JIS K2265-4: 2007 (Cleveland open cup (COC) method) determination of the flash point.

The pour point of the refrigerating machine oil may be-10 ℃ or lower, -20 ℃ or lower, or-50 ℃ or lower, or may be-40 ℃ or higher from the viewpoint of purification cost. The pour point in the present specification means a pour point according to JIS K2269: 1987 pour point.

The acid value of the refrigerator oil may be 1.0mgKOH/g or less, or 0.1mgKOH/g or less. The acid value in the present specification means an acid value according to JIS K2501: acid value determined in 2003.

The volume resistivity of the refrigerator oil may be 1.0 × 10⁹1.0 × 10 of not less than omega.m¹⁰Omega · m or more, or 1.0 × 10¹¹Omega · m or more. The volume resistivity in the present specification means a volume resistivity in accordance with JIS C2101: volume resistivity at 25 ℃ measured 1999.

The refrigerator oil may have a moisture content of 200ppm or less, 100ppm or less, or 50ppm or less, based on the total amount of the refrigerator oil.

The ash content of the refrigerator oil may be 100ppm or less, or 50ppm or less. Ash in the present specification means ash in accordance with JIS K2272: 1998 ash content determined.

The refrigerating machine oil is present in the state of a refrigerating machine working fluid composition mixed with a refrigerant in a refrigerating machine. That is, the refrigerating machine oil is used together with a refrigerant, and the working fluid composition for a refrigerator contains the refrigerating machine oil and the refrigerant. The content of the refrigerating machine oil in the working fluid composition for a refrigerator may be 1 part by mass or more, or 2 parts by mass or more, or 500 parts by mass or less, or 400 parts by mass or less, with respect to 100 parts by mass of the refrigerant.

Examples of the refrigerant include a hydrocarbon refrigerant, a saturated fluorinated hydrocarbon refrigerant, an unsaturated fluorinated hydrocarbon refrigerant, a fluorine-containing ether refrigerant such as perfluoroethers, a bis (trifluoromethyl) sulfide refrigerant, a difluoromethane iodide refrigerant, and a natural refrigerant such as ammonia or carbon dioxide.

The hydrocarbon refrigerant is preferably a hydrocarbon having 1 to 5 carbon atoms, more preferably a hydrocarbon having 2 to 4 carbon atoms. Specific examples of the hydrocarbon include methane, ethylene, ethane, propylene, propane (R290), cyclopropane, n-butane, isobutane (R600a), cyclobutane, methylcyclopropane, 2-methylbutane, n-pentane, and a mixture of 2 or more of these hydrocarbons. The hydrocarbon refrigerant is preferably a hydrocarbon refrigerant which is gaseous at 25 ℃ under 1 atmosphere, more preferably propane, n-butane, isobutane, 2-methylbutane or a mixture thereof.

The saturated fluorinated hydrocarbon refrigerant is preferably a saturated fluorinated hydrocarbon having 1 to 3 carbon atoms, more preferably 1 to 2 carbon atoms. Specific examples of the saturated fluorinated hydrocarbon refrigerant include difluoromethane (R32), trifluoromethane (R23), pentafluoroethane (R125), 1,1,2, 2-tetrafluoroethane (R134), 1,1,1, 2-tetrafluoroethane (R134a), 1,1, 1-trifluoroethane (R143a), 1, 1-difluoroethane (R152a), fluoroethane (R161), 1,1,1,2,3,3, 3-heptafluoropropane (R227ea), 1,1,1,2,3, 3-hexafluoropropane (R236ea), 1,1,1,3,3, 3-hexafluoropropane (R236fa), 1,1,1,3, 3-pentafluoropropane (R245fa), and 1,1,1,3, 3-pentafluorobutane (R365mfc), and mixtures of 2 or more thereof.

The saturated fluorinated hydrocarbon refrigerant is appropriately selected from the above depending on the application and the required performance. A saturated fluorinated hydrocarbon refrigerant such as R32 alone; r23 alone; r134a alone; r125 alone; r134a/R32 is a mixture of 60-80 mass%/40-20 mass%; R32/R125 is a mixture of 40-70 mass%/60-30 mass%; R125/R143a is a mixture of 40 to 60 mass%/60 to 40 mass%; r134a/R32/R125 ═ 60%/30%/10% by mass of the mixture; a mixture of R134a/R32/R125 in an amount of 40 to 70 mass%/15 to 35 mass%/5 to 40 mass%; and a mixture of 35 to 55 mass%/1 to 15 mass%/40 to 60 mass% of R125/R134a/R143 a. The saturated fluorinated hydrocarbon refrigerant may further specifically be a mixture of R134a/R32 ═ 70/30 mass%; a mixture of R32/R125 ═ 60/40 mass%; a mixture (R410A) of R32/R125 ═ 50/50 mass%; a mixture (R410B) of R32/R125 ═ 45/55 mass%; a mixture (R507C) of R125/R143a ═ 50/50 mass%; a mixture of R32/R125/R134a ═ 30/10/60 mass%; a mixture of R32/R125/R134a ═ 23/25/52 mass% (R407C); a mixture of R32/R125/R134a ═ 25/15/60 mass% (R407E); a mixture (R404A) of R125/R134a/R143a of 44/4/52 mass%, and the like.

The unsaturated fluorinated Hydrocarbon (HFO) refrigerant is preferably an unsaturated fluorinated hydrocarbon having 2 to 3 carbon atoms, more preferably fluoropropene, and still more preferably fluoropropene having a fluorine number of 3 to 5. The unsaturated fluorinated hydrocarbon refrigerant is preferably any 1 or a mixture of 2 or more of 1,2,3,3, 3-pentafluoropropene (HFO-1225ye), 1,3,3, 3-tetrafluoropropene (HFO-1234ze), 2,3,3, 3-tetrafluoropropene (HFO-1234yf), 1,2,3, 3-tetrafluoropropene (HFO-1234ye), and 3,3, 3-trifluoropropene (HFO-1243 zf). From the viewpoint of the physical properties of the refrigerant, the unsaturated fluorinated hydrocarbon refrigerant is preferably 1 or 2 or more selected from the group consisting of HFO-1225ye, HFO-1234ze and HFO-1234 yf. The unsaturated fluorinated hydrocarbon refrigerant may be vinyl fluoride, preferably 1,1,2, 3-trifluoroethylene.

The refrigerator oil and the working fluid composition for a refrigerator according to the present embodiment can be suitably used for refrigerators such as air conditioners having reciprocating or rotary hermetic compressors, refrigerators, open or hermetic automobiles, dehumidifiers, water heaters, freezers, refrigerated warehouses, vending machines, display cases, chemical plants, and refrigerators having centrifugal compressors.

Fig. 1 is a schematic diagram showing an example of a configuration of a refrigerator to which a refrigerator oil and a working fluid composition for a refrigerator according to the present embodiment are applied. As shown in fig. 1, the refrigerator 10 includes, for example, at least: the refrigerant compressor 1, the gas cooler 2, the expansion mechanism 3 (a capillary tube, an expansion valve, etc.), and the evaporator 4 are connected in this order by the flow path 5. In the above-described refrigerant cycle system, first, the high-temperature (generally 70 to 120 ℃) refrigerant discharged from the refrigerant compressor 1 into the flow path 5 becomes a high-density fluid (supercritical fluid or the like) in the gas cooler 2. Then, the refrigerant is liquefied through a narrow flow path of the expansion mechanism 3, and further vaporized in the evaporator 4 to a low temperature (normally-40 to 0 ℃).

In the refrigerant compressor 1 shown in fig. 1, a small amount of refrigerant coexists with a large amount of refrigerating machine oil under high temperature (generally 70 to 120 ℃). The refrigerant discharged from the refrigerant compressor 1 to the flow path 5 is gaseous, and contains a small amount (usually 1 to 10%) of the refrigerator oil in the form of mist, but a small amount of the refrigerant is dissolved in the mist of the refrigerator oil (point a in fig. 1). Next, in the gas cooler 2, the gaseous refrigerant is compressed to become a high-density fluid, and a large amount of refrigerant coexists with a small amount of refrigerating machine oil under a relatively high temperature condition (about 50 to 70 ℃) (point b in fig. 1). Further, a mixture of a large amount of refrigerant and a small amount of refrigerating machine oil is sent to the expansion mechanism 3 and the evaporator 4 in this order, rapidly becomes a low temperature (usually-40 to 0 ℃) (points c and d in fig. 1), and is returned to the refrigerant compressor 1 again.

The refrigerating machine oil of the present embodiment can be used together with the above-described refrigerant, and is particularly suitable for use together with a hydrocarbon refrigerant in terms of cooling-temperature characteristics and compatibility at the time of mixing the refrigerant. From the same viewpoint, the working fluid composition for a refrigerator particularly preferably contains a hydrocarbon refrigerant.

Examples

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples.

Refrigerator oils having the compositions shown in tables 1 to 4 (base oil, mass% based on the total amount of the base oil, and refrigerator oil, mass% based on the total amount of the refrigerator oil) were prepared using the components shown below. In all of the refrigerator oils of examples, comparative examples and reference examples, 0.1 mass% of 2, 6-di-t-butyl-p-cresol and 0.3 mass% of glycidyl neodecanoate were added.

(base oil)

A1: ester of neopentyl glycol with n-octanoic acid (kinematic viscosity at 40 ℃ C.: 7.4 mm)²S, nonpolar index: 38.5)

A2: ester of neopentyl glycol with 2-ethylhexanoic acid (kinematic viscosity at 40 ℃ C.: 7.5 mm)²S, nonpolar index: 38.5)

A3: ester of 2-ethylhexanol and 2-ethylhexanoic acid (kinematic viscosity at 40 ℃ C.: 2.7 mm)²S, nonpolar index: 41)

a 1: ester of pentaerythritol with mixed fatty acids of 2-ethylhexanoic acid/3, 5, 5-trimethylhexanoic acid (mass ratio: 50/50) (kinematic viscosity at 40 ℃ C.: 67.4 mm)²S, nonpolar meansNumber: 65)

(additives)

B1: 3- (Di-isobutoxy-thiophosphoryl mercapto) -2-methyl-propionic acid (compound represented by the following formula (3))

C1: tricresyl phosphate

The refrigerator oils of examples, comparative examples and reference examples were evaluated for wear resistance by the following procedure. The results are shown in tables 1 to 4.

(evaluation of abrasion resistance)

The FALEX Pin/Vee-Block test was performed. At a rotation speed: 290rpm, temperature: 60 ℃, oil mass: after running-in operation was carried out for 5 minutes under a load of 300lbf under an air atmosphere of 120mL, the load was gradually applied, and the load (lbf) at the time of wear was taken as the wear load. As the test piece, an ASTM standard piece was used. The wear load was determined as a relative value when the additive B1 and/or the additive C1 were contained, assuming that the wear load was 100 when the additive B1 and the additive C1 were not contained (comparative example 1, comparative example 2-1, comparative example 3-1, or reference example 2). The larger the value of the wear load, the greater the effect of improving the wear resistance.

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

As shown in examples 1, 2-2 and 3, it was confirmed that a large effect of improving the wear resistance was obtained by adding the compound represented by the formula (1) to a low-viscosity refrigerator oil. On the other hand, as shown in reference examples 1 and 2, it was confirmed that in the case of a non-low-viscosity refrigerator oil, even if the compound represented by formula (1) is added, the effect of improving the wear resistance is small as compared with the case of a low-viscosity refrigerator oil.

The refrigerator oils of examples 2-1, 2-2 and 3, comparative examples 2-1, 3-1 and 3-2 and reference examples 1 and 2 were also evaluated for wear resistance by the procedure shown below. The results are shown in Table 5.

(evaluation of abrasion resistance)

The abrasion resistance was evaluated by a high speed four ball test according to ASTM D4172-94. The hard ball was SUJ2, and the wear scar diameter (mm) of the fixed ball was measured by performing a test under conditions of a test oil amount of 20mL, a test temperature of 80 ℃, a rotation speed of 1200rpm, a load of 196N, and a test time of 15 minutes. A smaller value of the wear scar diameter indicates more excellent wear resistance.

[ Table 5]

4 kinds of refrigerating machine oils similar to those of examples 2-1 and 2-2 were obtained, except that the content of B1 in the refrigerating machine oil of example 2-1 or 2-2 was 0.05 mass% or 0.1 mass%. The kinematic viscosity at 40 ℃ of these refrigerator oils was 10mm²The ratio of the water to the water is less than s. These refrigerator oils were confirmed to have the same effects of improving wear resistance and abrasion resistance as in examples 2-1 and 2-2, but it was found that stability tends to deteriorate when the content of B1 is increased.

4 kinds of refrigerator oils similar to those of examples 2-1 and 2-2 were obtained except that the compound represented by the following formula (4) was used in place of B1 in the refrigerator oils of examples 2-1 and 2-2. The kinematic viscosity at 40 ℃ of these refrigerator oils was 10mm²The ratio of the water to the water is less than s. These refrigerator oils were confirmed to be the same as those of example 2-1Or 2-2, the same effect of improving abrasion resistance and abrasion resistance.

Further, 8 kinds of refrigerator oils similar to those of examples 2-1 or 2-2 were obtained except that C1 was replaced with triphenyl phosphate, tris (propylphenyl) phosphate, tris (butylphenyl) phosphate, or triphenyl thiophosphate in the refrigerator oils of examples 2-1 or 2-2. The kinematic viscosity at 40 ℃ of these refrigerator oils was 10mm²The ratio of the water to the water is less than s. These refrigerator oils were also confirmed to have the same effects of improving wear resistance and abrasion resistance as in examples 2-1 and 2-2.

Description of the reference numerals

A1 … refrigerant compressor, a2 … gas cooler, a3 … expansion mechanism, a 4 … evaporator, a 5 … flow path, and a 10 … refrigerator.

Claims

1. A refrigerator oil, comprising:

a base oil comprising an ester of an alcohol and a fatty acid, and

a compound represented by the following formula (1),

the kinematic viscosity of the refrigerator oil at 40 ℃ is 10mm²(ii) a ratio of (c) to(s) below,

2. The refrigerator oil of claim 1 wherein the alcohol comprises at least 1 selected from the group consisting of 1-and 2-membered alcohols.

3. The refrigerator oil of claim 1 or 2 wherein the fatty acid comprises a branched chain fatty acid.

4. The refrigerator oil according to any one of claims 1 to 3, wherein the base oil has a nonpolar index of 60 or less.

5. A working fluid composition for a refrigerator comprising a refrigerator oil and a refrigerant, the refrigerator oil comprising: a base oil comprising an ester of an alcohol and a fatty acid, and a compound represented by the following formula (1), wherein the kinematic viscosity of the refrigerator oil at 40 ℃ is 10mm²(ii) a ratio of (c) to(s) below,

6. The working fluid composition for refrigerators according to claim 5, wherein the alcohol comprises at least 1 selected from the group consisting of 1-and 2-membered alcohols.

7. The working fluid composition for refrigerators according to claim 5 or 6, wherein the fatty acid comprises a branched fatty acid.

8. The working fluid composition for refrigerators according to any one of claims 5 to 7, wherein the base oil has a nonpolar index of 60 or less.